DRILL (VERSIONS) Russian patent published in 2012 - IPC B23B51/02 

FIELD: process engineering.

SUBSTANCE: drill consists of shank and working part comprising chip removal flutes. Note that drill end has cutting and drilling edges arranged in different planes. In compliance with first version, working part is composed of three and more screw rectangular strips twisted in vertical plane relative to proper axis of symmetry and bent in screw lines on cylindrical mandrel in transverse direction and sequentially interconnected over the entire length of working part by their lateral sides. In compliance with another version, working part is made up of three and more helical trapezoid sheets of curvilinear convex or concave shape circumscribed by curves varying in order and degree of curvature with centers located inside and outside working part cross-section.

EFFECT: expanded performances.

2 cl, 11 dwg